The ore forming fluid geochemistry is an important branch of fluid geology. In recent years, among which the studies on precipitation mechanisms of metal elements has been paid attention to. Emphasis are placed on boiling and mixing of fluid controls on hydrothermal ore deposits.In this paper, some new advances in the boiling and mixing of fluids have been reviewed. The cooling resulted from temperature drop is not most effiective in precipitation some metal elements. Boiling of hydrothermal solution is perhaps the most effective ore depositional mechanism in many boiling hydrothermal systems, epithermal systems, and porphyry copper molybdenum deposits.With the result that mineralization is characterized by high grade, large intensity, and well developed vertical ore zoning. Its small influence range and short lived time restrict its role played in ore deposition. Mixing of hydrothermal solutions may be responsible for many hydrothermal deposits formation. Its larger influence range and long lived time is perhaps one of very important mechanisms for many large and superlarge deposits.